Title:
Long Term Durability of Synthetic Fibers in Concrete
Author(s):
Anil Khajuria, Kailash Bohra, and P. Balaguru
Publication:
Symposium Paper
Volume:
126
Issue:
Appears on pages(s):
851-868
Keywords:
accelerate aging; admixtures; air entrainment; durability; flexural strength and toughness; slump; synthetic fibers; Materials Research
DOI:
10.14359/2419
Date:
8/1/1991
Abstract:
Durability of fibers in concrete is a concern for nonmetallic fibers. This paper presents the results of durability studies conducted for synthetic fibers made of Nylon 6, polypropylene, and polyester. Long-term durability was estimated using an accelerated aging process. In this process, the specimens were stored in lime-saturated water maintained at 50 C. The integrity and the effectiveness of the fibers were studied using flexural toughness of 100 x 100 x 360-mm prisms tested under four-point loading. The concrete was designed for a 28-day compressive strength of 20 MPa, which is commonly used for field applications. A higher-than-normal fiber content of 4.75 kg/m3 (approximately 0.5 volume percent) was used to obtain consistently measurable toughness index values. All the fibers were 19 mm long. Nylon 6 and polyester fibers were made of single filaments, whereas polypropylene fibers were fibrillated. The results indicate that, at a fiber loading of 4.75 kg/m3, all three fibers provide post-crack resistance. Nylon 6 and polypropylene fibers are durable in alkaline environment present in concrete. This is demonstrated by the effectiveness of fibers measured in terms of flexural toughness values and the general load-deflection response. Specimens with polyester fibers had some loss of ductility when subjected to accelerated aging.